News Scan for Nov 30, 2017

Gene study tracks insecticide resistance across Africa

In the largest-ever genetic study of mosquitoes, researchers tracked the movement of insecticide resistance between different African regions and identified several rapidly evolving resistance genes that could be used to develop new tools for tracking resistance, monitoring insecticide use, and developing new control methods. The team from the Wellcome Trust Sanger Institute reporting its findings yesterday in Nature.

The investigators collected Anopheles gambiae mosquitoes, a species that transmits malaria, from 15 locations across eight African countries and sequenced the DNA of 765 of the insects. Their analysis found extreme genetic diversity, much higher than the team expected, compared with most other animal species, a factor that enables rapid evolution.

Sequencing also revealed rapid evolution of several genes that had previously been linked to insecticide resistance. The variants were emerging independently in different parts of Africa and were also being spread across different African regions during mosquito migration.

Martin Donnelly, PhD, study author who is with the Liverpool School of Tropical Medicine, said in a Sanger Institute press release, "Our study highlights the severe challenges facing public efforts to control mosquitoes and to manage and limit insecticide resistance."Nov 29 Natureabstract Nov 29 Sanger Institute press release

In other malaria developments, a collection of seven review articles published in PLoS Medicine today spells out a new research agenda for eliminating and eradicating malaria. The reports are from the Malaria Eradication Scientific Alliance, which began discussing the agenda, conducting six panels and including input from 180 experts.

The efforts are a follow-up of a collection of nine reports published in 2011 that identified knowledge gaps about the disease and key strategies and tools to control it.

Regina Rabinovich, MD, from the Harvard T.H. Chan School of Public Health, who led the group, said the papers provide a framework for research funders, the World Health Organization, and individual countries. Nov 30 PLoS Medicinereport Nov 30 PLoS press release

Analysis of university mumps outbreak shows no asymptomatic cases

A mumps outbreak earlier this year at the University of Washington in Seattle involved no asymptomatic students who shed the virus, a study today in Morbidity and Mortality Weekly Report (MMWR) concludes.

The first case was reported to public health officials on Feb 8, and by Jul 19, 42 cases were reported—16 of them confirmed. Of the 42 cases, 32 (63%) involved university fraternity or sorority members. All patients had received two or more doses of measles, mumps, and rubella (MMR) vaccine, according to current recommendations.

In response to the outbreak, local public health officials provided supplemental MMR doses to 235 members of eight fraternity or sorority houses reported the most cases. Researchers swabbed the inside cheek of 160 of these students, and all swabs came back negative for mumps virus.

The authors concluded, "Mumps outbreaks have increased in recent years in the United States; from 2015 through 2016, the proportion of outbreak-related cases increased from 63% to 78%. Further evaluations to better understand the prevalence of mumps virus shedding among vaccinated populations are needed to guide outbreak surveillance and control."Dec 1 MMWR report

Gavi to introduce typhoid vaccines into developing nations

Gavi, the Vaccine Alliance, has allocated $85 million for introducing typhoid conjugate vaccines into low-income nations, where millions of children are at risk for the disease, the organization announced today in a news release.

A new typhoid conjugate vaccine manufactured by Bharat Biotech International Ltd and first licensed in India in 2013 is currently under review for pre-qualification by the World Health Organization. Vaccines from five additional manufacturers are also under development and expected to be available from 2018 to 2022, the release says. Gavi expects the first countries to apply in 2018 and vaccine rollout to happen in 2019.

"Typhoid fever imposes a dramatic burden on children in the poorest nations affecting countries, communities and families," said Ngozi Okonjo-Iweala, MD, Gavi board chair. "This vaccine will be a lifesaver for millions of children, especially those living without access to clean water or sanitation."

"This vaccine is safe, effective and can provide lasting protection,” said Seth Berkley, MD, Gavi CEO. "The growing spread of drug resistant strains of typhoid is a major threat, not just to individuals but also to our efforts to control the disease, and requires us to prioritise prevention strategies. Strong coverage through routine immunisation together with efforts to improve access to clean water and hygiene will play a key role in dramatically reducing the disease."Nov 30 Gavi news release